Gas mask



FIG. 1 is a frontal upward leftward perspective view of a gas mask according to my design;

FIG. 2 is a frontal elevational view thereof;

FIG. 3 is a right elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design of a gas mask, as shown and described. 